Low-Protein Diet: Bad for Women's Bones?
Written by Editor   
Thursday, November 26, 2015 12:48 PM

Lifestyle factors such as diet can modify the risk of bone loss and fragility fractures.  The effects of some nutrients such as calcium and vitamin D on bone have been studied extensively, but less is known about other dietary components such as protein.  We've known since the 1920s that dietary protein affects calcium economy, but its exact role in calcium and skeletal metabolism has not been well defined.  This study demonstrates that a protein-restricted diet among young women resulted in significant decreases in calcium absorption, a finding that could have implications for women's skeletal health later in life, a researcher reported.

Limiting dietary protein to 0.7 g/kg for 6.5 weeks led to a decrease of -0.43% in intestinal calcium absorption.  This was accompanied by a decrease in urinary calcium by -0.48%, as well as a trend toward higher resorption, increased turnover, and a trend toward more negative bone balance.

Increased dietary protein is associated with a rise in urinary calcium, while with lower protein intake, urinary calcium declines. Previous studies found that there were no changes in intestinal calcium absorption with increases in dietary protein, which suggested that the increase in urinary calcium was caused by a loss of calcium in the skeleton.

"However, we have found that over the short term, increasing the dietary protein from 1 to 2.1 g/kg led to an increase in urinary calcium that was not associated with a rise in bone resorption. Rather, the increase in urinary calcium can be explained by a concomitant increase in calcium absorption in the intestine," she explained.

Source:  http://www.medpagetoday.com/MeetingCoverage/ASBMR/54071